Hand operated endless trencher

ABSTRACT

A portable trencher having a base member upon which is mounted a pair of chains which pass through the base member and are entrained about a pair of opposing sprockets. One of the sprockets is mounted to the top of the base member and operably connected with a motor mounted thereon. The other member is mounted below the base. The chains include cutting teeth and are connected together by means of a plurality of spacer members.

, United States Patent [191 Wolfston, Jr.

[ HAND OPERATED ENDLESS TRENCHER [76] Inventor: Carl E. Wolfston, Jr., 214 Easton Rd., Thornburg, Pa. 15205 [22] Filed: Aug. 4, 1971 [21] Appl. No.: 168,854

[52] US. Cl. 37/86, 37/191 A [51] Int. Cl E02f 5/06 [58] Field of Search, .Q 37/83, 86, 191 A, 37/94 [56] References Cited UNITED STATES PATENTS 7 3,624,935 12/1971 Lawrence 37/86 3,593,804 7/1971 Snider 37/191 A X 3,266,179 8/1966 Golden 37/86 3,054,198 9/1962 George et a1. 37/191 A X 2,031,279 2/1936 Newman 37/191 A [451 Oct. 9, 1973 FCREIGN PATENTS OR APPLICATIONS 1,523,492 3/1968 France 37/86 Primary ExaminerRobert E. Pulfrey Assistant ExaminerClifford D. Crowder Attorney-Thomas C. Wettach [57 ABSTRACT A portable trencher having a base member upon which is mounted a pair of chains which pass through the base member and are entrained about a pair of opposing sprockets. One of the sprockets is mounted to the top of the base member and operably connected with a motor mounted thereon. The other member is mounted below the base. The chains include cutting teeth and are connected together by means of a plurality of spacer members.

1 Claim, 2 Drawing Figures PATENTED 9|973 3,783.58 1

Fig. 2

INVENTOR.

Carl E. Wo/fsfon HAND OPERATED ENDLESS TRENCHER The present invention relates to a powered trencher and, in particular, to a powered portable trencher.

It is well known that many devices for digging large trenches exist and are in common usage. These devices include powered conveyor shovel combinations, shovels, or plow arrangements. For the most part these machines are quite well adapted for use on large construction projectssuch as cable laying along highways, canals, etc. However, the same machines are not compatible to the smaller construction projects that normally must be done by hand.

Smaller construction projects are usually found to exist around the home or in light construction. This type of construction usually includes such things as underground watering systems, underground cables for outdoor lighting, drain pipes, etc. Normally these projects must be accomplished by means of hand digging. The larger machines are both too costly to operate on the smaller jobs and tend to create an excavation and overburden that is too large. As is well known, hand digging is both time consuming and tiring. It also tends to create excavations that are larger than necessary.

The present invention overcomes the problems associated with small trench excavation by providing a small portable powered trencher. The invention provides a means for trenching and meeting exacting size requirements, thus eliminating large openings as well as overburdens. The present invention further provides a tool by which one man can do a small trenching project in a very short time.

Generally, the present invention includes a base or support member to which is mounted a drive means, for example an electric motor or gasoline engine. Directly coupled to or through a clutch arrangement to the drive means is a driving sprocket. The driving sprocket is supported, preferably, on a bearing mount. Depending from the bottom of the base and below the drive sprocket is a support arm having rotatably mounted at its end a driven or idlersprocket. Entrained about the driving and driven sprockets is a dual chain. The dual'chain comprises a pair of chains having cutting teeth mounted thereon similar to a chain saw. The two chains are connected together with a plurality of spacer mambers. To the base is mounted a handle which is located about the center of gravity of the unit.

By providing the present invention with an adjustable support arm and linkage adjustments to the dual chain, the cutting depth can be adjusted. Also by replacing the dual chain with one of a different length and width the trench size can specifically meet a particular requirement. The portable trencher provides a trench which is of the exact dimensionsdepth and width. Because of the cutting teeth on the chain, a trench can be dug which has substantially parallel sides. The dirt is removed to the side of the trench in pulverized state thus eliminating the over burden problem but yet facilitating back fill.

Other features and advantages are clear from a perusal of the detailed description of a presently preferred embodiment taken in connection with the following drawings of which:

FIG. 1 is a front elevation of the portable trencher; and

FIG. 2 is a side elevation of the trencher shown in FIG. 1.

Referring to FIG. 1, the portable trencher includes a base or support plate 10. Preferably, the base is made from a steel plate to add rigidity to the system. A plate of for example 1 1 inch in thickness provides a very rigid support upon which to mount the various components which are subject, in some case, to fairly high torques.

To base 10 is mounted a motor 11. Motor 11 can be either electrical or of the small gasoline type. A fractional horsepower electrical motor has been found quite adequate for digging trenches up to 2 or 3 inches in width and up to about 6 inches in depth. Depending upon the type of soil, greater depths can be achieved. It is clear, however, that with the advent of small,

highly efficient and light weight gasoline engines, it is preferable to utilize the gasoline engine. Not only does this facilitate the portability of the trencher, but a higher horsepower engine can be utilized without excessive weight. For example, a small (1 to 2) horsepower engine provides a very flexible power source for a multiplicity of various jobs.

Sprocket 12 is mounted for rotation between a pair of bearings 13 and support 14. Bearing supports 14 are mounted tobase 10 by any convenient means. For example, supports 14 may be boltedor welded. Welding, of course, is preferable since it is better able to provide strength against the torque and shock the trencher encounters. Bearings 13 are preferably bolted to support 14 to facilitate removal or exchange of sprocket l2. Sprocket 12 is operably connected to drive means 11 by shaft 15 and coupling 16. Coupling 16 can include a clutch means for example a friction clutch to protect the engine from over-loading.

It is clear that a single support is utilizable where it is desired to mount the chain at the edge of base plate 10. However, it is' preferred that two supports be utilized because of the torque generally encountered in such a digging operation.

Base 10 includes a pair of openings 17 between supports 14 located below a tangent line drawn perpendicular to the base. Mounted to the bottom of the base and depending therefrom is arm 18. Arm 18 is located between the openings 17. At the lower end of arm 18 are a pair of idler sprockets 19 mounted bypins 20 there- 'through. Entrained about sprocket l2 and sprockets 19 mately every fourth pitch. It is also possible to utilize a single chain where the spacers span the width and are mounted to the links. Alternatively, a plurality of chains could be used. The length of the spacers determines the width of the chain assembly and accordingly the width of the trench. The cutting teeth are preferably of design similar to those used on chain saws. Not only do the teeth facilitate the actual trenching operation but cut through underground growth systems such as roots and the like. Further, they provide a very even cut along the vertical walls of the trench. Thus, the

teeth, in cooperation with the spacers provide an extremely uniform cut.

Sprocket 12 can be of the continuous type which would accomodate a large number of varying width chains. Sprocket 20 can be adjusted by varying the width between the assemblies by addition or deletion of a spacer member 24.

A shield 25 is mounted to the bearing supports 14 to protect the user from any dirt or debris that might be thrown up by the chain.

To facilitate the use of the trencher, it is adaptable to being mounted upon a small wheeled carriage. Suitable carriage means include power lawn mowers. The portable trencher can be directly bolted thereon to permit the overhang of cutting chain. Typically, a handle can be provided (not shown) which would span the length or width of the assembly.

While one embodiment of the invention has been shown and described, it may otherwise be embodied within the scope of the appended claims.

What is claimed is:

1. A hand operable power trenching apparatus comprising a base member having at least one opening therethrough, a drive means mounted on said base member, a drive sprocket rotatably mounted to said base and operably connected to said drive means, an arm depending from said base member having an idler sprocket rotatably mounted thereto, and a pair of chains entrained about said sprockets and passing through said opening and having a plurality of cutting teeth and spacer members, said cutting teeth being mounted to links of said chains and said spacer members being mounted to extend between and above links of said chains. 

1. A hand operable power trenching apparatus comprising a base member having at least one opening therethrough, a drive means mounted on said base member, a drive sprocket rotatably mounted to said base and operably connected to said drive means, an arm depending from said base member having an idler sprocket rotatably mounted thereto, and a pair of chains entrained about said sprockets and passing through said opening and having a plurality of cutting teeth and spacer members, said cutting teeth being mounted to links of said chains and said spacer members being mounted to extend between and above links of said chains. 